Hydrocarbon reforming



G. EGLOFF HYDROCARBON REFORM'ING Filed Aug. l2, 1940 u ocr. 6, 1942.

/iiw R. fa Q m f m m ,f M K a w E e um. m d w ww L\ N @HDMI A N MIMI mm1 HNHK mw QN m llll l .m N Y lm. V lllllmmw. B NN QNR. NN QN QNS@ m. \N Q\\ w @1 QN m mmwn R QMNSQU QNSE smxn sw Patented Oct. 6, 1942 *DROCARBON REFORMING Gustav Egloff, Chicago, lll., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application August 12, 1940, Serial No. 352,223

5 Claims.

This invention relates to a process for reforming hydrocarbon distillate boiling substantially in the gasoline range to improve the antiknock qualities thereof and at the sametime to increase the quantity of high antiknock gasoline obtainable from a mixture of naphtha and higher boiling hydrocarbon oil. More specically, it relates to the catalytic conversion of such hydrocarbon distillates largely from petroleum sources, although similar suitable stocks from other hydrocarbon sources may be treated.

In one specific embodiment the present invention comprises a process for converting a hydrocarbon distillate boiling substantially within the gasoline range to improve the antiknock qualities thereof which comprises treating a mixture of said distillate and a higher boiling distillate fraction containing naphthenic hydrocarbon in the presence of a powdered catalytic agent in a primary cracking step under conditions of temperature and pressure adequate to effect substantial increase in the octane number, adding to the reaction products an additional quantity of powdered catalytic agent, subjecting the mixture to catalytic cracking conditions of temperature and pressure and recovering the gas and gasoline formed.

The invention is further understood by reference to the accompanying drawing which is diagrammatic and should not be construed as limiting it to the exact or relative dimensions given therein.

The hydrocarbon distillate used for reforming may comprise any gasoline or naphtha fraction boiling substantially within the gasoline range, The material may be of either straight run or cracked origin and may have an end-point slightly above the gasoline range, say for example, approximately 450 F. The naphtha is introduced through line I, valve 2, pump 3 to coil 4 which is disposed in heater 5. A higher boiling fraction of hydrocarbon oil containing substantial quantities of naphthenic hydrocarbons boiling, for example, within the kerosene or gas oil range, is introduced through line 6 containing valve 'I and pump 8. The powdered catalyst, by means of which the conversion is to be effected, is introduced from catalyst charger 9 through line I containing valve II, pump I2 and valve I3. The mixture is heated in coil 4 to a temperature within the range of approximately 500-1200 F. and usually within the range of 'ZOO-1100" F. whereby substantial reforming of the naphtha is eiected. The pressures used may range from substantially atmospheric to 1000 pounds per square inch. The reaction mixture passes through line I4, valve I and valve 23 to coil I6 which is disposed in heater II. An additional quantity of powdered catalyst is added to the reaction products from catalyst charger I8 through line I9 containing valve 20, pump 2| and valve 22. The temperature in coil I6, which is the secondary cracking stage, is within the range previously indicated for cracking coil 4, but need not be the same as is used in coil 4, The temperature is adjusted in this coil to eiect a maximum degree of catalytic cracking of the constituents of the reaction products from coil 4 which boil substantially above the gasoline range. ently.of the conditions in the primary cracking stage, although they may be affected to a certain y extent by the conditions employed in the primary stage.

A portion of the recycle oil from line 4'I may be introduced into line I4. This serves the dual purpose of further converting the4 recycle oil into additional quantities of gasoline and offering a means of controlling the temperature conditions in coil I6. The pressure maintained in coil I6 may be substantially lower than that in coil 4 and usually is atmospheric or slightly superat- I mospheric, of the order of 50-150 pounds per square inch. The reaction products pass through line 24 containing valve 25 to chamber 26. The

` spent catalyst as such or suspended in a portion of the residual oil may be withdrawn through line 21 and valve 28. The vaporous portion of reaction products is passed through line 29 and valve 30 to fractionator 3I. Gasoline and gas are recovered through line 32 containing valve 33, condenser 34 and valve 35. It is collected in receiver 36 and the gasoline may be withdrawn to suitable stabilizers or further equipment not shown through. line 3l and valve 38. A portion of the receiver gases may be passed through line 39 containing valve 40 to suitable gas recovery system not shown. A portion ofthe gas may be passed through line 4I containing valve 42,

pump 43 and valve 44 to line I and thus returned to the primary cracking step. ,This gas may serve the purpose of increasing the life of the catalytic agent as well as entering into the reaction whereby a portion of it is converted to liquid hydrocarbons of the gasoline boiling range. A portion of the fractionator bottoms is removed through line 45 and valve 46. An additional portion may be recycled to the secondary cracking step through line 41 containing valve 48, pump 49 and valve 50. This recycling serves These conditions are chosen lndependthe purpose of assisting in regulating the temperature of the reaction products in line I4 .and also of eiecting a further conversion of the high boiling oil to additional quantities of gasoline and gas.

The catalyst used in the present process may vary considerably in composition and this may depend to a certain extent upon the operating conditions to be employed and the properties of the finished gasoline which are desired. Among the catalytic agents are, for example, the socalled silica-alumina, silica-zirconia, silica-alumina-zirconia, etc., type which are made by' compositing silica and one or more of the other components by the separate or simultaneous precipitation of the components under such conditions that a finely divided powder of particle size'approaching colloidaldimensions is obtained. This may be followed by suitable washing and drying steps whereby the ne state of subdivision is retained and whereby alkali metal ions are substantially removed. Promoting oxides of other Y elements such as chromia, molybdena, tungsten,

uranium, vanadia, titania and thoria may also be added to this composite. The exact amount of promoting oxide is relatively minor, usually within the range of approximately 0.1-% by Weight of the total composite.

Another type of catalyst which has been foun to be useful, particularly when converting straight run naphthas comprises a relatively inactive carrier such as alumina, zirconia, .titania, zinc oxide, magnesia and the like having deposited thereon promoting compounds and particularly the oxides of metals appearing in the left-hand column of Groups IV, V and VI of the Periodic Table. This type of catalyst may also be used in admixture with the silica-alumina, etc., type.

Still another type of catalytic agent comprises the so-ca1led acid-treated'clays which are prepared'by chemical treatment of naturally occurring earths such as montmorillonite clays, etc.

The catalytic agents described are not necessarily equivalent in their action and should not be so construed. The operating conditions under which the best results may be obtained with any given catalyst may, vary considerably with the catalyst composition and the properties of the resulting products may also be affected both by th'e catalytic agent and the conditions of operation.

The amount of catalyst used depends upon the type and composition, the charging stock, and the operating conditions, and is within the limits of approximately 0.1-10% of the charging stock.

mixed with an additional quantity of approximately 1% of powdered catalyst. Insufilciently converted oil is also added to the secondary step and the temperature maintained in the cracking coil is of the order of 975 F., the pressure being substantially atmospheric. Gasoline and gas are recovered and a portion of the gas is returned to the primary reforming step. The higher boiling bottoms from the fractionator are returned to the secondary cracking step. Catalyst suspended in residual oil is removed from the vaporizing chamber and recovered by filtration, being thereafter reactivated by treatment with an oxygen-containing gas. The octane number of the resulting product is 79 and a yield of 85% of gasoline may be obtained.

Erample II A Mid-Continent cracked gasoline of 68 octane number is treated with approximately 25% of Mid-Continent gas oil at a temperature of 1025 F. using 1% of silica-alumina cracking catalyst. An additional 1% of cracking catalyst is added to the reaction products and the mixture is passed to a secondary cracking step at a temperature of 850 F. and a pressure of substantially atmospheric. Insuficiently converted oil is recycled to .the secondary cracking step. The octane number of recovered gasoline is 80 and the yield based on the original gasoline charge is 108%.

I'claim as my invention i 1. A hydrocarbon conversion process which comprises subjecting a hydrocarbon distillate The following examples are illustrative only and should not be construed as limiting the lnvention to the exact materials, catalytic agents or temperature and pressure conditions setl forth therein.

Example I mixture may be heated to approximately 105l0 F. at approximately 300 pounds per square inch ,V pressure in'aprirnary cracking stage and is then passed to a secondary, cracking step after being comprising naphtha and a heavier naphthenic oil to catalytic reforming in a primary reaction zone in the presence of a powdered dehydrogenating catalyst, supplying the resulting conversion products and catalyst to a secondary reaction zone and' therein continuing the conversion in the presence of a powdered cracking catalyst.

2. The process of claim 1 further characterized in that said dehydrogenating catalyst comprises alumina and chromia.

3. The process of claim 1 further characterized in that said cracking catalyst comprises silica and alumina.

4. The process of claiml further characterized in that said secondary reaction zone is maintained at a lower temperature and pressure than said primary reaction zone.

5. A hydrocarbon conversion process which `comprises subjecting a hydrocarbon distillate comprising naphtha and a heavier naphthenic oil to catalytic reforming in a primary reaction zone in the presence of a powdered dehydrogenating catalyst, supplying the resulting conversion products and catalyst to a secondary reaction zone and therein continuing the conversion in the presence of a powdered cracking catalyst, separating conversion products from the last named reaction zone into cracked vapors and residue containing the mixed catalysts, fractionating said `cracked vapors to form reilux condensate, supplying reux condensate to said secondary reaction zone, cooling and condensing the fractionated vapors, separating the resulting distillate from undissolved and uncondensed gases, and returning at'least a portion of said undissolved and uncondensed gases to the primary reaction zone.

GUSTAV EGLOFF. 

